The present invention relates to a PGA socket for use in connecting a PGA (Pin Grid Array) package provided with a plurality of pins in a grid array fashion to a printed circuit board and the like.
Of late years notebook type personal computers and the like have been required to be thin. As means for achieving thin thickness, attempts to reduce thickness of PGA sockets for use in connecting a PGA package to a printed circuit board have been made.
The PGA socket includes a base housing formed with contact holes in a grid array fashion, a plurality of contacts located in the contact holes, a cover housing formed with through holes in a grid array fashion through which pins of a PGA package can be inserted, and a sliding mechanism for sliding the cover housing over the base housing. Each contact includes a press-fitting portion for press-fitting the contact to be engaged in the base housing, a contact portion for being in contact with a pin of a PGA package, and a soldering portion for soldering the contact to a printed circuit board and the like.
Pins of the PGA package are inserted into the PGA socket through the through holes of the cover housing by zero insertion force to a position in which the pins of the PGA package face the contact portions of the contacts. The cover housing is slid over the base housing by sliding mechanism of the PGA socket and then the pins of the PGA package come in contact with the contact portions of the contacts to be electrically connected therewith.
However, there is a limit to the reduction in thickness of PGA socket because of a construction thereof where a definite length of the soldering portion projects into an outside of the base housing.
It is an object of the present invention to reduce thickness of PGA sockets in order to achieve thin thickness of notebook type personal computers and the like.
A PGA socket of the present invention comprises a base housing formed with a large number of contact holes in a grid array fashion, a cover housing located to overlap the base housing and formed with a large number of through holes in a grid array fashion through which pins of a PGA package can be inserted, a sliding mechanism for sliding the cover housing over the base housing, and plurality of contacts held in the contact holes of the base housing and coming in contact with pins of a PGA package by sliding movement of the cover housing caused by the sliding mechanism, wherein a whole body of each of the contacts is substantially housed in the contact hole of the base housing and a surface of each of the contacts is on a plane substantially equal to an outer surface of the base housing opposite a surface of the base housing overlapping the cover housing.
According to the PGA socket, the whole body of the contact is substantially housed in the contact hole of the base housing and a soldered surface of the contact is on a plane substantially equal to an outer surface of the base housing. Ensuring electrically come in contact with the contacts and a printed circuit board and the like, reduction in thickness of PGA socket by a thickness equivalent to a portion of a conventional contact projecting into outside of the base housing can be realized. As a result, reduction in thickness of various kinds of equipment on which the PGA sockets are mounted can be realized.
The contact of the present invention held in the above-mentioned PGA socket to be in contact with a pin of a PGA package comprises a plate-like base portion and a tail portion provided continuously at one end of the base portion to substantially traverse the base portion in an orthogonal direction. The contact is in a shape to fit for the above-mentioned PGA socket because of the tail portion having a surface traversing the base portion in an orthogonal direction.
The contact of the present invention held in the above-mentioned PGA socket to be in contact with a pin of a PGA package comprises a plate-like base portion, a projecting portion provided continuously in the base portion to extend in a direction substantially equal to the base portion, a turned portion provided continuously at one end of the base portion to face the base portion, and a tail portion provided continuously at the other end of the base portion not to face the base portion. According to the contact, reduction in thickness of PGA socket can be realized. Also, it is possible to prevent flux from adhering on a contact surface for being in contact with a pin of a PGA package, thereby preventing a loose electrical connection of the pin and the contact.